2 Найдите корень уравнения: a) 13/56 + y = 34/56 ; б) x − 7/90 = 39/90 ; в) 27/48 + 15/48 − a = 17/48 ; г) b + 14/23 − 3/23 = 20/23 .

1. a) $$\frac{13}{56} + y = \frac{34}{56}$$

$$y = \frac{34}{56} - \frac{13}{56}$$

$$y = \frac{34-13}{56}$$

$$y = \frac{21}{56}$$

$$y = \frac{3}{8}$$

Ответ: $$\frac{3}{8}$$

2. б) $$x - \frac{7}{90} = \frac{39}{90}$$

$$x = \frac{39}{90} + \frac{7}{90}$$

$$x = \frac{39+7}{90}$$

$$x = \frac{46}{90}$$

$$x = \frac{23}{45}$$

Ответ: $$\frac{23}{45}$$

3. в) $$\frac{27}{48} + \frac{15}{48} - a = \frac{17}{48}$$

$$\frac{27+15}{48} - a = \frac{17}{48}$$

$$\frac{42}{48} - a = \frac{17}{48}$$

$$a = \frac{42}{48} - \frac{17}{48}$$

$$a = \frac{42-17}{48}$$

$$a = \frac{25}{48}$$

Ответ: $$\frac{25}{48}$$

4. г) $$b + \frac{14}{23} - \frac{3}{23} = \frac{20}{23}$$

$$b + \frac{14-3}{23} = \frac{20}{23}$$

$$b + \frac{11}{23} = \frac{20}{23}$$

$$b = \frac{20}{23} - \frac{11}{23}$$

$$b = \frac{20-11}{23}$$

$$b = \frac{9}{23}$$

Ответ: $$\frac{9}{23}$$